Patients who are unconscious or experiencing severe medical conditions may require that breathable gas such as oxygen, anesthetic gas and/or air be directed into the mouth, nose or airway to assist or facilitate breathing. Many respiratory systems include a humidification system to warm and impart humidity to the breathable gas before it is provided to the patient. The humidification system typically employs a chamber for holding water and a heater unit adapted to heat the chamber. The breathable gas passes through the chamber where it is heated and humidified and carried to a patient by an inspiratory limb of a breathing circuit, which may also include an expiratory limb to carry expelled air and other gas(es) from the patient back to the ventilator.
The chamber is typically disposable and may be selectively coupled to the heater unit in thermal communication with a heated plate thereof. The heater unit contains the necessary electrical and electronic components to regulate the temperature of the heated plate as well as heating circuits of the breathing circuit, if desired. The heater units can be quite heavy, but typically need to be mounted to a support, such as a pole or a ventilator used to drive the breathable gas into the chamber and on to the patient. A mounting mechanism, such as a hitch associated with the heater unit and a receiver associated with the support, may be employed to mount the heater unit. The hitch may be secured to the free end of a mounting bracket secured to the heater unit, with the receiver defining a keyway or channel configured to slidably receive the hitch therein.
While a hitch and receiver mounting mechanism is useful, there are situations where the hitch could come out of the receiver leading to unintended consequences. By way of example, while moving the support to which the heater unit is mounted, such as when moving a patient from one room to another, bumps or other obstacles may be encountered which might jar the hitch loose from the receiver. A locking mechanism could be associated with the mounting mechanism so as to secure the hitch in the receiver during use, thus avoiding undesired release of the hitch therefrom. However, a locking mechanism could also interfere with sliding the hitch into the receiver.
The present invention provides a lockable mounting mechanism which is adapted to avoid undesired release of the hitch from the receiver, but which does not interfere with sliding the hitch into the receiver. To that end, and in accordance with the principles of the present invention, a pivoting locking member is associated with the hitch which can pivot between a locked and an unlocked position, and further has associated therewith a camming surface positioned, when the locking member is out of the unlocked position, to engage against a reset surface of the receiver to be automatically pivoted into the unlocked position as the hitch is slid into the receiver. As a result, the mounting mechanism is provided with a locking mechanism to be secured in place during use, but which does not interfere with sliding the hitch into the receiver.
The camming surface may be defined on a cam member which rotates with the locking member. In the unlocked position of the locking member, the cam member is oriented such that the camming surface is inboard of the reset surface. As a result, the camming surface will pass by the reset surface of the receiver without impacting thereagainst as the hitch is slid into the receiver. The receiver may include a slot or opening sized to receive the cam member therein and supporting the reset surface such as along an edge thereof. If the locking member is not in the unlocked position, the camming surface will be outboard of the reset surface such that attempts to slide the hitch into the receiver will cause the camming surface to impact against the reset surface of the receiver. The camming surface and reset surface cooperate such that continued sliding of the hitch into the receiver will cause the cam member to rotate the camming surface inboard of the reset surface to thereby automatically pivot the locking member towards the unlocked position and orient the cam member to pass into the slot. The hitch will then continue its sliding movement into the receiver without the need to manually readjust the locking member.
The receiver is further provided with a capture portion such as a recess adjacent the slot into which a portion of the cam member rotates, such as into frictional engagement therewith, when the locking member is pivoted into the locking position. With the hitch seated in the receiver, the capture portion is aligned with the cam member such that rotation thereof brings a portion of the cam member into the capture portion. The hitch will then be locked into the receiver until the locking member is pivoted out of the locked position to thereby release the hitch for movement out of the receiver. While the hitch is locked in the receiver, the support may be moved about without worrying about bumps or other obstacles causing the hitch to prematurely come loose from the receiver. Yet, the locking mechanism does not interfere with sliding the hitch into the receiver in the event the locking member is not in the unlocked position. In accordance with a further aspect of the present invention, the locking member may include one or more spring-loaded arms along one edge which bear against a set plate in the unlocked position of the locking member so as to minimize the risk of the locking member inadvertently coming out of the unlocked position.
Advantageously, the locking member pivots in a plane generally parallel with the path along which the hitch slides into the receiver. The locking member may thus rotate in either a clockwise or counterclockwise direction. The receiver is advantageously provided with a pair of opposed capture portions such that upon rotation of the locking member in either direction out of the unlocking position will bring the cam member portion into one of the capture portions such that the locking member has two locking positions. Further advantageously, the slot is provided with two reset surfaces, each aligned with a respective capture portion, and the cam member has two camming surfaces, such that if the locking member is out of the unlocked position in either direction, one of the camming surfaces engages one of the reset surfaces to automatically realign the cam member for unimpeded entry into the slot so that the hitch can be readily slid into the receiver.
By virtue of the foregoing, there is thus provided a lockable mounting mechanism which is adapted to avoid undesired release of the hitch from the receiver, but which does not interfere with sliding the hitch into the receiver. These and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof.